Small Tweaks

Also consider the following small, yet efficient tweaks:

• Eliminate excessive cryptographic routines that involve hard drives. To prevent the I/O on your SSD or HDD from contributing to the entropy pool, you can disable the add_random setting for your block devices:

# echo 0 > /sys/block/sda/queue/add_random

Linux uses the entropy pool for things like generating SSH keys, SSL certificates, or anything else crypto. Preventing your SSD from contributing to this pool probably isn't a security issue, but it will save you small amounts of I/O.

• Bring parallel drive probing back. It may seem surprising, but modern-day Linux distributions still probe ATA devices serially by default, which is called staggered spin-ups (SSS). This technique goes back to a time when spinning up multiple drives at once caused power usage peaks, and thus the Linux kernel avoided parallel probes. This behavior makes little or no sense on modern systems, especially if there are no rotational drives. Enabling probing ATA drives in parallel speeds up the boot process. First, check if the SSS flag is set in your system:

$ dmesg | grep SSS

If it is, add the libahci.ignore_sss=1 boot option to GRUB. A Linux system with several hard drives or SSDs will see a better boot time.

• Mount /tmp to RAM. Most Linux systems already use tmpfs (check it with $ df), but you can add another RAM-backed mount point to get rid of temporary runtime clutter that usually sits in /tmp:

$ echo "tmpfs /tmp tmpfs rw, nosuid,nodev 0 0" | sudo tee -a /etc/fstab

This way your system will clear everything found in /tmp upon every reboot. Doing the same for /var/tmp is not recommended as long as the /var/tmp directory is meant to store data persistently.

Conclusion

The very versatile Linux includes many modules, tools, and settings that allow you to tweak the system and improve performance. If you have a computer with insufficient memory or slower-than-expect I/O, or even if you just want to experiment to learn more about Linux, the techniques described in this article will help you take your first steps.